Why is the JButton btn[3][5] not getting placed on the position given in the setBounds() call?

Question

I am coding a program wich should contain multiple JButtons set next to each other. At first I wanted a 4 by 6 Grid. I have 3 classes: a Main clas containing the main method and a constructor call of the Gui class constructor. The Gui class should include all JObjects (JButtons) + the JFrame setup. Then there is a third ButtonPlacement class wich includes the setBounds method calls. As I ran the Code in Eclipse ervery Button in my Button Array was placed at the right position except the last one: btn[3][5]. It is as big as the whole JFrame.

class Main:

package pack1;

public class Main {

    public static void main(String[] args) {

        new Gui();
    }
}

class Gui:

package pack1;

import java.awt.Font;

import javax.swing.JButton;
import javax.swing.JFrame;

import pack1.ActionHandler;
import pack1.ButtonPlacement;

public class Gui {

    static JFrame jf;
    static JButton btn[][] = new JButton[4][6];
    JButton btnReset;

    public Gui() {

        jf = new JFrame();
        jf.setSize(500, 600);
        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jf.setResizable(false);
        jf.setLocationRelativeTo(null);



        for(int i = 0; i<4;++i) {
            for(int j = 0; j<6; ++j) {
            btn[i][j] = new JButton("btn" + i + j);
            btn[i][j].setVisible(true);
            btn[i][j].addActionListener(new ActionHandler());
            btn[i][j].setFocusPainted(false);
            btn[i][j].setContentAreaFilled(true);
            btn[i][j].setBorder(null);
            btn[i][j].setFont(new Font("Century Gothic", Font.PLAIN, 20));
            jf.add(btn[i][j]);
            }

        }

        ButtonPlacement.place();

        jf.setVisible(true);

    }

}

class ButtonPlacement:

package pack1;

import pack1.Gui;

public class ButtonPlacement {

    public static void place() {


        Gui.btn[0][0].setBounds(0, 140, 100, 60);
        Gui.btn[1][0].setBounds(100, 140, 100, 60);
        Gui.btn[2][0].setBounds(200, 140, 100, 60);
        Gui.btn[3][0].setBounds(300, 140, 100, 60);

        Gui.btn[0][1].setBounds(0, 200, 100, 60);
        Gui.btn[1][1].setBounds(100, 200, 100, 60);
        Gui.btn[2][1].setBounds(200, 200, 100, 60);
        Gui.btn[3][1].setBounds(300, 200, 100, 60);

        Gui.btn[0][2].setBounds(0, 260, 100, 60);
        Gui.btn[1][2].setBounds(100, 260, 100, 60);
        Gui.btn[2][2].setBounds(200, 260, 100, 60);
        Gui.btn[3][2].setBounds(300, 260, 100, 60);

        Gui.btn[0][3].setBounds(0, 320, 100, 60);
        Gui.btn[1][3].setBounds(100, 320, 100, 60);
        Gui.btn[2][3].setBounds(200, 320, 100, 60);
        Gui.btn[3][3].setBounds(300, 320, 100, 60);

        Gui.btn[0][4].setBounds(0, 380, 100, 60);
        Gui.btn[1][4].setBounds(100, 380, 100, 60);
        Gui.btn[2][4].setBounds(200, 380, 100, 60);
        Gui.btn[3][4].setBounds(300, 380, 100, 60);

        Gui.btn[0][5].setBounds(0, 440, 100, 60);
        Gui.btn[1][5].setBounds(100, 440, 100, 60);
        Gui.btn[2][5].setBounds(200, 440, 100, 60);
        Gui.btn[3][5].setBounds(300, 440, 100, 60);

    }

}

I expect the Button btn[3][5] at its position 300, 440 with its size 100, 60, but the button is as big as the JFrame.

I would like to do this without any layout Manager and I want to know, why the last setBounds call for btn[3][5] wont work. — Mcsim, Jul 16 '19 at 16:19
Just added `jf.setLayout(null);` in class Gui and it worked perfectly, but no idea why the placement worked for the other JButtons without that then. — Mcsim, Jul 16 '19 at 16:41
Which is exactly what you shouldn't be doing. This guarantees that the gui will look bad on all but one platform and that it will be difficult to maintain and enhance — Hovercraft Full Of Eels, Jul 16 '19 at 18:05

score -2 · Accepted Answer · answered Jul 16 '19 at 16:46

-2

Adding this to the class Gui let it work properly for me:

jf.setLayout(null);

answered Jul 16 '19 at 16:46

Mcsim

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*"work properly"* To 'work properly' a Swing/AWT GUI needs to use layouts. Java GUIs have to work on different OS', screen size, screen resolution etc. using different PLAFs in different locales. As such, they are not conducive to pixel perfect layout. Instead use layout managers, or [combinations of them](http://stackoverflow.com/a/5630271/418556) along with layout padding and borders for [white space](http://stackoverflow.com/a/17874718/418556). – Andrew Thompson Oct 11 '19 at 01:06

Why is the JButton btn[3][5] not getting placed on the position given in the setBounds() call?

1 Answers1